On 10/10/2017 22:13, Mathias Nyman wrote:
> On 10.10.2017 12:41, David Laight wrote:
>> From: Robin Murphy
>>> Sent: 09 October 2017 18:39
>> ...
>>>> - without the IOMMU, block sizes >=128K all settle down into a
>>>> suspiciously-periodic error every 2048 sectors.
>>
>> That stinks of being a problem where either the link TRB is part
>> way through a USB packet or where a buffer fragment crosses
>> a 64k boundary.
>>
>> Neither is allowed.
>>
>
> Those should be taken care of by the xhci driver already
>
> xhci_align_td() should make sure the link TRB is at packet boundary, and
> TRB_BUFF_LEN_UP_TO_BOUNDARY(addr) in xhci_queue_bulk_tx() should prevent
> crossing 64k boundary in a TRB when queuing it.
>
> more traces and logs of the VIA xhci controller could maybe tell something.
>
> with the latest kernel:
>
> echo 81920 > /sys/kernel/debug/tracing/buffer_size_kb
> echo 1 > /sys/kernel/debug/tracing/events/xhci-hcd/enable
> after failure:
> cat /sys/kernel/debug/tracing/trace
Unfortunately since the failure on my VL805 is during xhci init tracing doesn't
produce anything we don't already know..
# tracer: nop
#
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| / delay
# TASK-PID CPU# |||| TIMESTAMP FUNCTION
# | | | |||| | |
modprobe-964 [003] .... 240.271468: xhci_dbg_quirks: QUIRK:
Resetting on resume
modprobe-964 [003] .... 240.271471: xhci_dbg_init: // Halt the HC
modprobe-964 [003] .... 240.271477: xhci_dbg_init: // Reset the HC
And the associated DMA faults:
[ 265.286686] DMAR: DRHD: handling fault status reg 2
[ 265.286688] DMAR: [DMA Read] Request device [03:00.0] fault addr de28a000
[fault reason 01] Present bit in root entry is clear
I'll try and figure out exactly what de28a000 points at (or points after..).
Thanks.
--
Hao Wei
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